Testaceous (?), a. [L. testaceus, fr. testa a shell. See Testa.] 1. Of or pertaining to shells; consisted of a hard shell, or having a hard shell.
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2. (Bot. & Zoöl.) Having a dull red brick color or a brownish yellow color.
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Testaceous animals (Zoöl.), animals having a firm, calcareous shell, as oysters and clams, thus distinguished from crustaceous animals, whose shells are more thin and soft, and consist of several joints, or articulations, as lobsters and crabs.
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